1. Field of the Invention
The invention relates to techniques for producing mineral fiber mats.
2. Description of the Related Art
Industrially, these mats are obtained by a two-stage process. The production of the fibers themselves by drawing and solidifying of a molten inorganic material in a first stage, and then association of a vast number of fibers which are brought together to constitute the mat. Between the two stages, the glass fibers or rock fibers are wetted with a binder which will be polymerized upon emerging from the second stage. Once the mat is completed, it is necessary to trim off the longitudinal edges of the strips so that they are quite clean. This operation produces a residue, the edges of the mat, which desirably should be used again. Similarly, certain waste resulting from subsequent handling of the panels or rolls constitute by-products which should be recycled.
Until now, the first operation, i.e., the recycling of the waste from the edges, was carried out by shredding the waste and returning the flock upstream of the place where the mat is created. This simple operation does, however, have two drawbacks.
Firstly, the rate of flow of waste reintroduced into the mat is not even and the wastage should not have a density which differs too greatly from that of the mat into which it is introduced. Furthermore, the time which elapses between the time when the waste is cut downstream of the line and the time when it reaches an upstream location is quite prolonged so that it is impossible to introduce waste during a change in production if the difference in densities of the products being manufactured exceeds a certain threshold.
Second, with regard to the use of waste which is produced during surfacing operations, longitudinal trimming, packaging or even dispatch, it is very difficult and often requires a lot of human intervention to prepare the waste, store it after it has been reduced to flock, to take the decision to recycle it and finally carry this out.